Portable oxygen concentrator



FIG. 1 is a perspective view of the portable oxygen concentrator showing my new design;

FIG. 2 is a perspective view thereof from another angle;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a left side elevational view thereof;

FIG. 6 is a right side elevational view thereof;

FIG. 7 is a top plan view thereof; and,

FIG. 8 is a bottom plan view thereof.

The broken lines shown in the drawings represent portions of the portable oxygen concentrator that form no part of the claimed design. 

CLAIM The ornamental design for a portable oxygen concentrator, as shown and described. 